Greer is 5,11 180 he- when he was a rookie he weighed like 165- 170 - ie too small - it wasn't a height issue
McGee 5,9 200- now McGee is a little short but he stronger than most CBs and has good jumping ability
These players are average size for CBs not small- if you are looking for small check out last years Bills front seven except for Crowell they were all undersized